Timeline for Gibbs free energy intuition
Current License: CC BY-SA 4.0
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| S Jun 23, 2018 at 15:45 | history | edited | V.F. | CC BY-SA 4.0 |
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| S Jun 23, 2018 at 15:45 | history | suggested | Thomas Abshier | CC BY-SA 4.0 |
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| Jun 23, 2018 at 14:58 | review | Suggested edits | |||
| S Jun 23, 2018 at 15:45 | |||||
| Nov 30, 2014 at 15:24 | comment | added | jabirali | By the way, the quantity $H = U + PV$ that measures how much energy is left after accounting for volume changes under constant atmospheric pressure, is known as enthalpy. | |
| Nov 30, 2014 at 15:22 | comment | added | jabirali | Yeah, that sounds right! For a concrete example: when a chemical reaction produces gas, then the volume of your system increases. In order for this expansion to happen, then your system has to "push away" the atmosphere, which means that the system performs work on the environment. Conversely, if your chemical reaction consumes gas, then $\Delta V$ will be negative, and so the atmosphere will "push together" your system, and the environment performs work on your system. That's how the work $P\Delta V$ enters when you calculate changes in free energy $\Delta G$. | |
| Nov 30, 2014 at 13:32 | comment | added | user36790 | And who does work? The system? Or the surroundings?? | |
| Nov 30, 2014 at 13:29 | comment | added | user36790 | Sir, what does $PV$ mean? To me, $P\Delta{V}$ is the work and it does make sense. Does the former mean the work done against $P$ to make vol. $V$ from $0$ ?? | |
| Nov 30, 2014 at 10:42 | comment | added | jabirali | So processes that increase the Gibbs free energy can be shown to decrease the entropy of the universe, and that's why the second law of thermodynamics prevents it. | |
| Nov 30, 2014 at 10:36 | history | edited | jabirali | CC BY-SA 3.0 |
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| Nov 30, 2014 at 1:26 | history | edited | jabirali | CC BY-SA 3.0 |
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| Nov 29, 2014 at 17:01 | history | edited | jabirali | CC BY-SA 3.0 |
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| Nov 29, 2014 at 16:49 | history | answered | jabirali | CC BY-SA 3.0 |